Polarization element and projection display device

Abstract

A polarization element includes: a substrate; a plurality of convex line sections on one surface of the substrate and forming stripes in a plan view; and a multilayer thin line provided to each convex line section and extending along the convex line sections, wherein the multilayer thin line has a lower layer on the convex line section, and an upper layer stacked on the lower layer, the lower layer and the upper layer each have a first thin line on one side surface in a direction along a shorter dimension of the convex line section, and a second thin line on the other side surface, the materials of the lower layer first thin line and the upper layer first thin line are different from each other, and the materials of the lower layer second thin line and the upper layer second thin line are different from each other.

1. A polarization element comprising:
 a substrate; 
 a plurality of convex line sections disposed on one surface of the substrate so as to form substantial stripes in a plan view; and 
 a multilayer thin line provided to each of the convex line sections and extending along an extending direction of the convex line sections, 
 wherein the multilayer thin line has a lower layer thin line disposed on the convex line section, and an upper layer thin line stacked on the lower layer thin line, 
 the lower layer thin line and the upper layer thin line each have a first thin line disposed on one side surface out of both side surfaces in a direction along a shorter dimension of the convex line section, and a second thin line disposed on the other side surface, 
 materials of the first thin line belonging to the lower layer thin line and the first thin line belonging to the upper layer thin line are different from each other, and 
 materials of the second thin line belonging to the lower layer thin line and the second thin line belonging to the upper layer thin line are different from each other. 
 
     
     
       2. The polarization element according to  claim 1 , wherein
 the materials of the first thin line and the second thin line belonging to the lower layer thin line are the same, and 
 the materials of the first thin line and the second thin line belonging to the upper layer thin line are the same. 
 
     
     
       3. The polarization element according to  claim 1 , wherein
 the entire lower layer thin line is covered by the upper layer thin line. 
 
     
     
       4. The polarization element according to  claim 1 , wherein
 the first thin line and the second thin line are made of one of a light reflecting material having a relatively high light reflecting property and a light absorbing material having a relatively high light absorbing property. 
 
     
     
       5. The polarization element according to  claim 4 , wherein
 the first thin line and the second thin line belonging to the lower layer thin line are made of the light reflecting material, and 
 the first thin line and the second thin line belonging to the upper layer thin line are made of the light absorbing material. 
 
     
     
       6. The polarization element according to  claim 1 , wherein
 in the lower layer thin lines adjacent to each other, volumes of the first thin lines are different from each other, volumes of the second thin lines are different from each other, and volumes of the lower layer thin lines are substantially the same as each other, 
 the volumes of the first thin lines continuously descend in a direction in which a distance from one end of the substrate increases, and 
 the volumes of the second thin lines continuously descend in a direction in which a distance from the other end of the substrate increases. 
 
     
     
       7. The polarization element according to  claim 1 , wherein
 in the upper layer thin lines adjacent to each other, volumes of the first thin lines are different from each other, volumes of the second thin lines are different from each other, and volumes of the upper layer thin lines are substantially the same as each other, 
 the volumes of the first thin lines continuously descend in a direction in which a distance from one end of the substrate increases, and 
 the volumes of the second thin lines continuously descend in a direction in which a distance from the other end of the substrate increases. 
 
     
     
       8. The polarization element according to  claim 1 , further comprising:
 a protective film covering the convex line sections and the multilayer thin lines, 
 wherein in an area between the convex line sections and the multilayer thin lines adjacent to each other, there is formed a void section unfilled with the protective film. 
 
     
     
       9. The polarization element according to  claim 8 , wherein
 the protective films respectively covering the convex line sections and the multilayer thin lines adjacent to each other have contact with each other at the top of the void section to cover the void section. 
 
     
     
       10. The polarization element according to  claim 8 , wherein
 the protective film is formed from a translucent insulating material. 
 
     
     
       11. The polarization element according to  claim 4 , wherein
 the light reflecting material is selected from the group consisting of aluminum, gold, silver, copper, chromium, titanium, nickel, tungsten, and iron, and 
 the light absorbing material is selected from the group consisting of silicon, germanium, molybdenum, and tellurium. 
 
     
     
       12. A polarization element comprising:
 a substrate including a convex line section extending in a first direction; 
 a lower thin line including a first lower thin line disposed on one side of the convex line and a second lower thin line disposed on the other side of the convex line, the lower thin line extending in the first direction; and 
 a upper thin line including a first upper thin line stacked on the first lower thin line and a second upper thin line stacked on the second lower thin line, the upper thin line extending in the first direction, 
 wherein materials of the first lower thin line and the first upper thin line are different from each other, and 
 materials of the second lower thin line and the second upper thin line are different from each other. 
 
     
     
       13. A projection display device comprising:
 the polarization element according to  claim 12 .